1. Field of the Invention
The present invention relates to an antenna device for a portable terminal. Particularly, the present invention relates to an antenna device for a portable terminal, which allows a whip antenna and helical antenna of a terminal to be retracted/withdrawn along an extension from the terminal, while not requiring the antennas to protrude out of the terminal.
2. Description of the Related Art
Recently, portable terminals have been made to be multi-functional and downsized due to consumer demands. Particularly, such multi-functional terminals provide voice communication service, radio service, and MP3 music download service via Internet. Additionally, it is possible to obtain digital information about various data and images with ease from portable terminals, Personal Digital Assistants (PDAs), computers and notebook computers.
The portable terminals generally include a liquid crystal display (LCD) as a data output device. Conventionally, a keypad including a plurality of keys is used for the input of data.
In addition to the above, a portable terminal has an antenna device positioned in a suitable location in its main body for receiving signals transmitted from a counterpart terminal.
Antenna devices currently used for portable terminals may be classified as external antennas which protrude from the housing and internal antennas disposed inside the housing of a terminal. More particularly, external antennas include whip antennas and helical antennas. Internal antennas include inverted L antennas, planar inverted F antennas, diversity antennas and microstrip antennas.
Portable terminals with the above-described structure have spread quickly to consumers and are used widely. Also, there is a tendency to develop multi-functional portable terminals having various functions for satisfying the various needs of consumers in addition to simple communication service. For example, besides voice communication, additional services for users include video-on-demand (VOD) service, image communication service, digital camera function, Internet service, TV service, etc.
A portable terminal capable of TV service among the above additional services is referred to as a digital multimedia-broadcasting (DMB) terminal. A DMB terminal allows a user to watch TV programs through a display device, while also performing a mobile telecommunication function.
The portable terminal capable of TV service includes at least two Radio Frequency (RF) modules, because a frequency band necessary for transception of voice and data is different than a frequency band for TV broadcasting. The portable terminal capable of TV service is operated in a phone mode, waiting mode, and a broadcasting service mode, which is an image reception mode combined with a waiting mode.
Antennas for TV broadcasting signals include a helical antenna for exclusive use in a broadcasting service, which is mounted to a terminal, and an external antenna for exclusive use of broadcasting service. Regarding antenna devices for exclusive use in the broadcasting service, a retractable antenna having a whip antenna combined with a helical antenna is used widely.
As shown in FIG. 1, the helical antenna 2 is disposed at a suitable position in a portable terminal in order to receive signals transmitted from a counterpart sender.
The helical antenna 2 protrudes from the main body 1 of the terminal by a predetermined length in such a manner that the whip antenna 3 is retracted/withdrawn through it. Therefore, there are disadvantages in that the helical antenna 2 may be broken due to the retraction/withdrawal of the whip antenna 3. It is also inconvenient to carry the terminal 1 in a bag, pocket, etc. due to the helical antenna 2 protruding out of the terminal. Additionally, such a protruding portion may be damaged and broken if a user drops the terminal, and such an antenna makes it impossible to obtain an attractive design for the terminal.
As shown in FIG. 2, the antenna 4 for TV broadcasting signals includes a broadcasting signal-receiving module (not shown) embedded therein. The terminal 1 is equipped with an interface connector (not shown) for connecting the broadcasting signal receiving module with the external antenna for exclusive use in the broadcasting service. Additionally, a jack 4a of the external antenna 4 for exclusive use in the broadcasting service is connected with the interface connector (not shown), so as to receive TV broadcasting signals.
The multi-functional portable terminal as described above should have an antenna for general voice transception. Additionally, an antenna for exclusive use in the broadcasting service and designed for frequencies in radio and TV broadcasting service is mounted to the terminal, wherein the antenna for exclusive use in the broadcasting service is essential for satisfactory reception of broadcasting signals.
However, a conventional antenna for exclusive use in the broadcasting service is inconvenient to use, because it is too bulky when fixed to a terminal to permit the enjoyment of radio and TV services. Additionally, users must carry the antenna at all times even when it is not used, resulting in poor portability.
Further, it is necessary for users to carry a conventional antenna for exclusive use in the broadcasting service at all times in order to use it on demand. Therefore, there exists a great possibility of the losing of the antenna. Moreover, when a separate casing is provided in order to prevent the loss of antenna, an additional cost arises.